期刊文献+
共找到24,747篇文章
< 1 2 250 >
每页显示 20 50 100
乡村振兴与乡村旅游协同的测度与评价 认领
1
作者 生延超 杨睿 李梦琪 《湖南工业大学学报:社会科学版》 2021年第1期14-20,共7页
基于乡村振兴和乡村旅游二者的协同关系,构建乡村振兴与乡村旅游协同评价指标体系,并利用耦合协调模型,测度并评价2011—2018年我国乡村振兴和乡村旅游的耦合协调度。结果表明,就全国层面而言,乡村振兴和乡村旅游两者的耦合协调度呈递... 基于乡村振兴和乡村旅游二者的协同关系,构建乡村振兴与乡村旅游协同评价指标体系,并利用耦合协调模型,测度并评价2011—2018年我国乡村振兴和乡村旅游的耦合协调度。结果表明,就全国层面而言,乡村振兴和乡村旅游两者的耦合协调度呈递增趋势,大致可分为三个阶段:发展滞后的耦合阶段、失衡阶段和发展迅速的协调阶段;就区域来看,东、中、西三个地区乡村振兴与乡村旅游两大系统的综合水平得到了一定的发展,但耦合协调存在空间差异:东部地区处于乡村振兴驱动的初级协调状态,中部地区处于乡村振兴和乡村旅游驱动的中级协调状态,西部地区处于乡村旅游驱动的勉强协调状态;经济发展、政府扶持、资源禀赋是影响两大系统协同发展的重要因素。 展开更多
关键词 乡村振兴 乡村旅游 协同 耦合协调度
在线阅读 下载PDF
Synthesis, Characterization, Antimicrobial and DNA Binding Studies of a Tetradentate N2O2 Amino Acid Schiff Base and Its Coordination Compounds 认领
2
作者 Temitayo O. Aiyelabola Daniel P. Otto +2 位作者 Johan H. L. Jordaan Ezekiel O. Akinkunmi Idowu Olawuni 《生物化学进展(英文)》 2021年第1期30-51,共22页
<span style="font-family:Verdana;">Aminoethanoic acid undergoes condensation with 1,4-benzenedicarboxaldehyde</span><span><span><span style="font-family:""><sp... <span style="font-family:Verdana;">Aminoethanoic acid undergoes condensation with 1,4-benzenedicarboxaldehyde</span><span><span><span style="font-family:""><span style="font-family:Verdana;"> to form an O, N, N, O donor Schiff base, </span><i><span style="font-family:Verdana;">N,N'</span></i><span style="font-family:Verdana;">-di(carboxymethylene)</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">terephthalaldehyde, Ligand L. Coordination compounds of this Schiff base us</span><span><span style="font-family:Verdana;">ing Ni (II), Cu (II), </span><span style="font-family:Verdana;">VO</span><span style="font-family:Verdana;"> (IV) and Co (II) were then obtained </span><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;">. The</span></span><span style="font-family:Verdana;"> Schiff base and the complexes were evaluated for their antimicrobial and DNA binding abilities. Molecular docking studies of the ligand and synthesized compounds were also carried out. Evidence for the formation of the Schiff base coordination compounds and the coordinating atoms was obtained from </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H NMR, infrared and ultraviolet spectral data, EDX, EDTA complexometric titration and magnetic susceptibility measurement. The results obtained are consistent with octahedral geometry for Ni (II) complex</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the metal ion coordinating to one molecule of Ligand L</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> and</span></span></span><span style="font-family:Verdana;"><span style="f 展开更多
关键词 CT-DNA DNA Binding ANTIMICROBIAL Coordination Compound Molecular Docking Schiff Base
在线阅读 免费下载
Synthesis and Characterization of a Metal-Organic Framework Bridged by Long Flexible Ligand 认领
3
作者 Kawther Osman Ashiry Rasha Khalid Abbas 《高分子化学期刊(英文)》 2021年第1期1-9,共9页
3D supramolecular network with considerable volume pores was created via hydrogen bond & C-H</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;&qu... 3D supramolecular network with considerable volume pores was created via hydrogen bond & C-H</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">--</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">π. By </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">tightening </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">of The metal-organic frameworks (MOF) namely [Ni(μ-pmb)</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">(H</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O)</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">]</span><sub><span style="font-family:Verdana;">n</span></sub><span style="font-family:Verdana;"> (pmb = 3,5-bis(4-pyridylmethylenoxyl)</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">benzoate, that have been synthesized by hydrothermal method. Complex 1 crystallizes in triclinic P-1 space group and consists of 1D semi zigzag chain. 展开更多
关键词 Coordination Polymer Hydrogen Bond Metal-Organic Frameworks LIGAND
在线阅读 免费下载
Chemical functionalization of 2D black phosphorus 认领
4
作者 Yajuan Liu Muqing Chen Shangfeng Yang 《信息材料》 SCIE CAS 2021年第3期231-251,共21页
As an emerging two-dimensional material,black phosphorus(BP)has fascinating structure and electronic properties,affording broad applications in fieldeffect transistors,optoelectronic devices,energy devices,and biomedi... As an emerging two-dimensional material,black phosphorus(BP)has fascinating structure and electronic properties,affording broad applications in fieldeffect transistors,optoelectronic devices,energy devices,and biomedicines.However,the lone pair electrons of phosphorus atoms readily react with oxygen,so few-layer BP is easily oxidized and degraded when exposed to air.Therefore,the ambient stability of BP needs to be enhanced for its potential application.Chemical functionalization is one of the most effective methods for improving the ambient stability of few-layer BP.In this review,we provide a comprehensive overview of the chemical functionalization of BP,focusing on covalent and noncovalent functionalization and surface coordination.The influence of the functionalization pattern on the electronic properties and ambient stability of BP is summarized.Finally,the challenges and future development of chemical functionalization of BP are discussed. 展开更多
关键词 2D material black phosphorus chemical functionalization COORDINATION STABILITY
网络零售的经济学分析 认领
5
作者 王国顺 王瑾 《北京工商大学学报:社会科学版》 北大核心 2021年第1期105-113,共9页
网络零售是互联网与零售业融合发展的一种零售业态。在零售业转型升级的背景下,用经济学基本原理,从零售本质出发研究了网络零售的产生与发展。研究发现,网络零售是为了应对消费需求升级,运用互联网提升供需匹配效率而产生的,其交易环... 网络零售是互联网与零售业融合发展的一种零售业态。在零售业转型升级的背景下,用经济学基本原理,从零售本质出发研究了网络零售的产生与发展。研究发现,网络零售是为了应对消费需求升级,运用互联网提升供需匹配效率而产生的,其交易环节呈现出交易主体多元化、交易内容信息化、交易组织去中间化与再中心化的特征;网络零售的效率提升来自技术创新下的供求关系变动带来的供需边界拓展、供求关系重塑、分工协同效应与一体化发展;网络零售的虚拟性特征难以满足消费者多样化、瞬时化的需求,信息化水平不足以影响零售效率,组织形式平台化趋势容易导致垄断的出现,因此网络零售未来要通过打通实体要素与虚拟要素边界,推动全产业链的数字化转型,打造零售社群,加强对垄断与信息不当使用的规制,以提高供给质量,识别消费需求,进而推动零售效率提升。 展开更多
关键词 网络零售 分工 协同 效率 供需边界 时空价值 供求重塑
在线阅读 免费下载
Fe atoms anchored on defective nitrogen doped hollow carbon spheres as efficient electrocatalysts for oxygen reduction reaction 认领
6
作者 Panpan Su Wenjuan Huang +10 位作者 Jiangwei Zhang Utsab Guharoy Qinggang Du Qiao Sun Qike Jiang Yi Cheng Jie Yang Xiaoli Zhang Yongsheng Liu San Ping Jiang Jian Liu 《纳米研究:英文版》 SCIE EI CAS 2021年第4期1069-1077,共9页
Defective electrocatalysts,especially for intrinsic defective carbon,have aroused a wide concern owing to high spin and charge densities.However,the designated nitrogen species favorable for creating defects by the re... Defective electrocatalysts,especially for intrinsic defective carbon,have aroused a wide concern owing to high spin and charge densities.However,the designated nitrogen species favorable for creating defects by the removal of nitrogen,and the influence of defects for the coordination structure of active site and oxygen reduction reaction(ORR)activity have not been elucidated.Herein,we designed and synthesized a pair of electrocatalysts,denoted as Fe-N/C and Fe-ND/C for coordination sites of atomic iron-nitrogen and iron-nitrogen/defect configuration embedded in hollow carbon spheres,respectively,through direct pyrolysis of their corresponding hollow carbon spheres adsorbed with Fe(acac)3.The nitrogen defects were fabricated via the evaporation of pyrrolic-N on nitrogen doped hollow carbon spheres.Results of comparative experiments between Fe-N/C and Fe-ND/C reveal that Fe-ND/C shows superior ORR activity with an onset potential of 30 mV higher than that of Fe-N/C.Fe-ND sites are more favorable for the enhancement of ORR activity.Density functional theory(DFT)calculation demonstrates that Fe-ND/C with proposed coordination structure of FeN_(4-x)(0<x<4)anchored by OH as axial ligand during ORR,weakens the strong binding of OH^(*)intermediate and promotes the desorption of OH^(*)as rate-determining step for ORR in alkaline electrolyte.Thus,Fe-ND/C electrocatalysts present much better ORR activity compared with that of Fe-N/C with proposed coordination structure of FeN_(4). 展开更多
关键词 atom ic iron nitrogen defect coordination environment hollow carbon spheres oxygen reduction reaction
国家科技创业政策协调性研究——基于政策工具视角 认领
7
作者 李鹏利 张宝建 +2 位作者 刘晓彤 陈劲 裴梦丹 《科学管理研究》 北大核心 2021年第1期2-10,共9页
科技创业政策是科技型创业企业开展创业活动和实现创新发展的重要支撑。鉴于当前学界对国家科技创业政策的总体性和系统性把握不足,以及由此带来的政策效力分析的局限,采用政策文本内容分析法从政策非均衡性、冗余性、缺失性、矛盾性和... 科技创业政策是科技型创业企业开展创业活动和实现创新发展的重要支撑。鉴于当前学界对国家科技创业政策的总体性和系统性把握不足,以及由此带来的政策效力分析的局限,采用政策文本内容分析法从政策非均衡性、冗余性、缺失性、矛盾性和错位性等方面对我国2006~2020年间国家层面发布的科技创业政策进行了系统梳理。研究发现供给型、需求型和环境型三类政策工具的使用均存在非均衡性;供给型和环境型政策工具的使用存在过溢现象,而需求型政策工具则存在缺失现象;央—地政府政策存在错位性且部分政策内容呈现矛盾性。结论能够补充国家科技创业政策的相关理论研究,并为科技创业主体的双创实践提供制度参考。 展开更多
关键词 科技创业政策 协调性 政策工具
从分离到融合:健康治理体系的路径选择 认领
8
作者 王海燕 潘琦 《沈阳师范大学学报:社会科学版》 2021年第1期55-60,共6页
2018年我国成立的应急管理部,目的是提高突发事件的风险管理能力,为部门间协同配合、动态管理创造了条件。新型冠状病毒引起的肺炎疫情暴发以来,该部门全面协调全国上下人力、物力、财力,积极应对疫情,动态把握疫情实施情况并为我们战... 2018年我国成立的应急管理部,目的是提高突发事件的风险管理能力,为部门间协同配合、动态管理创造了条件。新型冠状病毒引起的肺炎疫情暴发以来,该部门全面协调全国上下人力、物力、财力,积极应对疫情,动态把握疫情实施情况并为我们战胜疫情抢得先机。反思疫情,民众意识到“维持生存”的思想观念需要转变,“病有所医”的医疗体制、一元供给的医疗服务已经难以满足人们的需求。基于此,构建预防、治疗与康复三位一体的健康治理格局,以普及预防知识、全面协调治理和保证政策落地的方式补偿健康治理转型过程中体系不完备的问题,是医疗卫生体制改革的一个出路。 展开更多
关键词 健康治理 预防 健康管理 协调
在线阅读 免费下载
贵州乌蒙山区人口-经济-农业生态环境耦合协调关系研究 认领
9
作者 程东亚 李旭东 《世界地理研究》 北大核心 2021年第1期125-135,共11页
山区人地矛盾突出,其人口、经济与生态环境可持续发展存在矛盾,解决三者之间的协调发展问题,是山区生态文明建设和资源环境建设中的重点。文章选取贵州乌蒙山区人口、经济、农业生态环境相关数据,采用熵值法、耦合度、协调度等方法测度... 山区人地矛盾突出,其人口、经济与生态环境可持续发展存在矛盾,解决三者之间的协调发展问题,是山区生态文明建设和资源环境建设中的重点。文章选取贵州乌蒙山区人口、经济、农业生态环境相关数据,采用熵值法、耦合度、协调度等方法测度人口、经济与农业生态环境发展趋势,并进一步探究其耦合度与协调度发展特征。研究得出以下结论:①2005-2015年贵州乌蒙山区人口、经济发展总体向好,农业生态环境发展较为滞后,期间Ipop、Ieco分别提升0.259、0.487,Iagr下降0.398。②2005-2015年贵州乌蒙山区人口、经济、农业生态环境关系日益密切,协调性总体不断增强,但系统协调度明显低于耦合度,系统是一种不均衡的发展趋势。③2005-2015年贵州乌蒙山区人口、经济、农业生态环境协调性具有空间差异,大致呈东高西低,七星关、赤水和习水等县区协调度较高。④2005-2015年贵州乌蒙山区县域耦合度提升到高级耦合阶段,但多数县区仍处于初级协调阶段。 展开更多
关键词 人口 经济 农业生态环境 耦合度 协调度 贵州乌蒙山区
SHARING IS CARING 认领
10
作者 Lu Yue Tian Jilin 《北京周报:英文版》 2021年第10期16-17,共2页
Regional coordination creates a win-win situation forthose at home and abroad One notable feature of China's growth since the late 1970s is that certain regional pinpoints often take the lead in carving out a new ... Regional coordination creates a win-win situation forthose at home and abroad One notable feature of China's growth since the late 1970s is that certain regional pinpoints often take the lead in carving out a new path for development before creating a lane for others to catch up, the end goal being that of synchronized growth.Throughout the last four decades。 展开更多
关键词 COORDINATION creating CATCH
中国城市异速生长的空间异质性及作用机理研究 认领
11
作者 张永芳 张跃胜 冯云廷 《统计与信息论坛》 北大核心 2021年第4期93-103,共11页
中国城市化高速发展,使其城市人地矛盾出现日益激化现象。人地关系的协调发展与有限资源的可持续利用,将直接影响到社会经济健康持续发展。结合生物学异速生长方程,利用反映器官相对生长速度的异速生长系数来表征城市人口与土地的相对... 中国城市化高速发展,使其城市人地矛盾出现日益激化现象。人地关系的协调发展与有限资源的可持续利用,将直接影响到社会经济健康持续发展。结合生物学异速生长方程,利用反映器官相对生长速度的异速生长系数来表征城市人口与土地的相对生长速度。整合中国293个地级及以上城市面板数据,运用空间探索性数据分析方法与夏普利值分解法对中国异速生长系数区域差异空间异质性特征及成因进行系统测定。研究结果发现:中国各地级市异速生长系数的空间自相关性较强,“高—高”集聚和“低—低”集聚态势显著。中国大量城市处于第一象限H-H高高集聚区,多分布在中国的东中部地区,主要为土地显著扩张型和土地明显扩张型城市。城市地理区位和土地市场化程度两个影响因素相互助力,共同改变城市人地异速关系现状。其中土地市场化率对异速生长系数的贡献度最高,达43.89%,是主要影响因素;行政区位对异速生长系数的贡献度达16.19%,是次要影响因素。政策建议东部发达地区合理安排不同用地性质土地,结合土地置换,提高土地利用效率,使有限的稀缺土地效用最大化发挥。中部地区赶超区加快实施存量建设用地挖潜力度,并积极调整产业结构,促进产业转型升级。西部后进区加快土地市场化建设进程,完善西部土地利用规划,避免土地盲目开发与使用。 展开更多
关键词 异速生长 人地关系 地域分异 协调性 夏普利值分解
在线阅读 下载PDF
A chemically stable nanoporous coordination polymer with fixed and free Cu^(2+)ions for boosted C_(2)H_(2)/CO_(2)separation 认领
12
作者 Si Chen Nibedita Behera +7 位作者 Chao Yang Qiubing Dong Baishu Zheng Yingying Li Qi Tang Zhaoxu Wang Yanqing Wang Jingui Duan 《纳米研究:英文版》 SCIE EI CAS 2021年第2期546-553,共8页
Safely and highly selective acetylene(C_(2)H_(2))capture is a great challenge,because of its highly explosive nature,as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dio... Safely and highly selective acetylene(C_(2)H_(2))capture is a great challenge,because of its highly explosive nature,as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dioxide(CO_(2)).Adsorption separation has shown a promising future.Herein,a new nanoporous coordination polymer(PCP)adsorbent with fixed and free Cu ions(termed NTU-66-Cu)was prepared through post-synthetic approach via cation exchanging from the pristine NTU-66,an anionic framework with new 3,4,6-c topology and two kinds of cages.The NTU-66-Cu shows significantly improved C_(2)H_(2)/CO_(2)selectivity from 6 to 32(v/v:1/1)or 4 to 4_(2)(v/v:1/4)at low pressure under 298 K,along with enhanced C_(2)H_(2)capacity(from 89.22to 111.53 cm^(3)·g^(-1)).More importantly,this observation was further validated by density functional theory(DFT)calculations and breakthrough experiments under continuous and dynamic conditions.Further,the excellent chemical stability enables this adsorbent to achieve recycle C_(2)H_(2)/CO_(2)separation without loss of C_(2)H_(2)capacity. 展开更多
关键词 nanoporous coordination polymer high porosity new topology post-synthetic approach C_(2)H_(2)/CO_(2)separation
甘肃省主要城市空间扩张协调性分析 认领
13
作者 蔡喜琴 《地理空间信息》 2021年第1期128-130,I0007,共4页
在全国地级以上城市以及典型城市群空间格局监测项目中,根据城市用地增长弹性系数判断城市空间扩展的协调性。结果表明,2000-2016年全国大多数城市用地增长弹性系数大于最优值1.12。分析了城市用地增长弹性系数最优值的来源以及城市空... 在全国地级以上城市以及典型城市群空间格局监测项目中,根据城市用地增长弹性系数判断城市空间扩展的协调性。结果表明,2000-2016年全国大多数城市用地增长弹性系数大于最优值1.12。分析了城市用地增长弹性系数最优值的来源以及城市空间扩张与人口增长关系的相关研究成果,将人均城市用地面积与城市用地增长弹性系数结合起来,用于城市空间扩张协调性分析,并在甘肃省主要城市进行了空间扩张分析实验。 展开更多
关键词 城市 空间扩张 人口增长 协调性 甘肃省
在线阅读 下载PDF
Interaction between urbanization and eco-environment in the Tibetan Plateau 认领
14
作者 FENG Yuxue LI Guangdong 《地理学报:英文版》 SCIE 2021年第2期298-324,共27页
A scientific evaluation of the broad reciprocal influences between urbanization and the eco-environment in the Tibetan Plateau region is of great significance for increasing the speed and quality of urbanization as we... A scientific evaluation of the broad reciprocal influences between urbanization and the eco-environment in the Tibetan Plateau region is of great significance for increasing the speed and quality of urbanization as well as restoring and improving the eco-environment.Based on a thorough look at the progress made by research on interactions between urbanization and the eco-environment in the Tibetan Plateau region,this article attempts to construct a complete analytical model of the reciprocal influences that can achieve the whole process of analyzing evaluation indexes,quantifying coupling coordination,identifying coupling types,exploring decoupling paths,and predicting future trends.Using multi-scale analysis of the Tibetan Plateau and its provinces and prefecture-level units as a means of comparison,we attempt to clarify differences at different scales,identify problem areas and propose targeted improvement measures.The result shows that the urbanization evaluation indexes for the Tibetan Plateau at different scales rise in stages and that the urbanization index for Qinghai is higher than for Tibet;the changes in the eco-environment index of the two regions are also different,with a downward trend in Qinghai and a trend toward stability in Tibet,and with stratification in the eco-environment indexes of prefecture-level units;the degree of coupling coordination between urbanization and the eco-environment at different scales in the Tibetan Plateau region is increasing overall,with the type of coordination changing from uncoordinated deterioration to borderline uncoordinated deterioration,and ultimately changing into scarcely coordinated development,which basically puts the region into the logging urbanization category;and the urbanization and eco-environment indexes display a dynamic trend of alternating between strong decoupling and weak decoupling,indicating that there is a negative reciprocal influence between urbanization and eco-environment at different scales and that the phenomenon of passive urbanization 展开更多
关键词 URBANIZATION ECO-ENVIRONMENT coupling coordination degree DECOUPLING PREDICTION Tibetan Plateau
中国不同类型城市低碳、环保与发展的协调性分析 认领
15
作者 郑林昌 李泽阳 付加锋 《财经理论研究》 2021年第1期12-23,共12页
为判断我国城市低碳、环保与发展的协同状况,利用构建的城市低碳环保发展评价模型和协调度模型,对我国285个地级市以上城市的低碳环保发展指数和指数间协调性进行评估和测算,结果表明:我国城市低碳指数、环保指数与发展指数具有一定差异... 为判断我国城市低碳、环保与发展的协同状况,利用构建的城市低碳环保发展评价模型和协调度模型,对我国285个地级市以上城市的低碳环保发展指数和指数间协调性进行评估和测算,结果表明:我国城市低碳指数、环保指数与发展指数具有一定差异,发展指数不仅评价得分高于低碳指数和环保指数,增速总体也明显快于两指数;低碳指数、环保指数与发展指数之间协调性相对较好,三大指数之间协调性不断提高,且总体具有城市规模越大指数协调性越好的特点;但城市低碳生产指数与低碳消费指数、环境污染指数与环境管理指数的协调性相对较差,不过近期已有所改善。 展开更多
关键词 城市 低碳环保发展指数 协调度
在线阅读 免费下载
Strain and interfacial engineering to accelerate hydrogen evolution reaction of two-dimensional phosphorus carbide 认领
16
作者 黄韬 思源 +5 位作者 吴宏宇 夏立新 蓝郁 黄维清 胡望宇 黄桂芳 《中国物理B:英文版》 SCIE EI CAS 2021年第2期449-456,共8页
Hydrogen,regarded as a promising energy carrier to alleviate the current energy crisis,can be generated from hydrogen evolution reaction(HER),whereas its efficiency is impeded by the activity of catalysts.Herein,effec... Hydrogen,regarded as a promising energy carrier to alleviate the current energy crisis,can be generated from hydrogen evolution reaction(HER),whereas its efficiency is impeded by the activity of catalysts.Herein,effective strategies,such as strain and interfacial engineering,are imposed to tune the catalysis performance of novel two-dimensional(2D)phosphorus carbide(PC)layers using first-principle calculations.The findings show that P site in pristine monolayer PC(ML-PC)exhibits higher HER performance than C site.Intriguingly,constructing bilayer PC sheet(BL-PC)can change the coordinate configuration of P atom to form 3-coordination-P atom(3-co-P)and 4-coordination-P atom(4-co-P),and the original activity of 3-co-P site is higher than the 4-co-P site.When an external compressive strain is applied,the activity of the 4-co-P site is enhanced whereas the external strain can barely affect that of 3-co-P site.Interestingly,the graphene substrate enhances the overall activity of the BL-PC because the graphene substrate optimizes the?GH*value of 4-co-P site,although it can barely affect the HER activity of 3-co-P site and ML-PC.The desirable properties render 2 D PC-based material promising candidates for HER catalysts and shed light on the wide utilization in electrocatalysis. 展开更多
关键词 phosphorus carbide hydrogen evolution reaction(HER) coordination configuration ELECTROCATALYSIS first principle calculations
显色法评价酚类化合物对废弃钻井液中铁离子的配位作用 认领
17
作者 赵福荣 贾继国 +3 位作者 郑丽 王登治 贾彦强 王浩 《化工技术与开发》 CAS 2021年第1期8-10,共3页
经絮凝压滤处理后的废弃钻井液中,含有未沉淀的铁离子、铝离子等高价金属离子,若将其用于配制钻井液,则会与PAM、改性淀粉等发生作用,抑制其伸展,降低其增黏、提切等作用。本文依据酚中的羟基能够与金属离子形成稳定络合物的特性,以及... 经絮凝压滤处理后的废弃钻井液中,含有未沉淀的铁离子、铝离子等高价金属离子,若将其用于配制钻井液,则会与PAM、改性淀粉等发生作用,抑制其伸展,降低其增黏、提切等作用。本文依据酚中的羟基能够与金属离子形成稳定络合物的特性,以及酚类化合物与铁盐可形成蓝紫色至棕褐色络合物的特性,而铁盐本身的颜色为浅黄色,设计了显色法,用于评价酚类化合物对废弃钻井液中铁离子的配位作用,从而用于指导处理废弃钻井液中的铁离子屏蔽剂的评价和使用。 展开更多
关键词 酚类化合物 显色 铁离子 配位
在线阅读 下载PDF
Dynamic Analysis of Supply and Demand Coupling of Ecosystem Services in Loess Hilly Region:A Case Study of Lanzhou,China 认领
18
作者 LI Pengjie LIU Chunfang +1 位作者 LIU Licheng WANG Weiting 《中国地理科学:英文版》 SCIE 2021年第2期276-296,共21页
The relationship between the supply and demand for ecosystem services(ESs)is a key issue for the rational allocation of natural resources and optimisation of sustainable development capacity.This paper investigateed t... The relationship between the supply and demand for ecosystem services(ESs)is a key issue for the rational allocation of natural resources and optimisation of sustainable development capacity.This paper investigateed the dynamic evolution features of supply and demand of four ESs in Lanzhou of China,namely,water supply,food supply,carbon fixation and soil retention services.The crosssectional data of 2005 and 2017 were used for calculating ESs value and its supply and demand through ArcGIS software,InVEST model,elastic coefficient model and coupling coordination model.Results showed that:1)from 2005 to 2017,the supply of water supply services increased,the demand of soil retention services decreased,and the supply and demand of food supply and carbon fixation services increased.The high-value areas of service supply were mainly distributed in the rocky mountain areas in the southeast and northwest with high vegetation coverage,while the high-value areas of demand were mainly distributed in the urban areas and surrounding areas with high population density.2)There were five different types of coupling relations.Water supply service was dominated by a negative coupling type D,which means that the decrease in demand for ESs has had a positive response on the supply of ESs.Negative coupling type C was the main type of food supply and carbon fixation services,which means that the increase in demand for ESs has had a negative response on the supply of ESs.All three services were supplemented by a positive coupling type A,which means that the increase in demand for ESs has had a positive response on the supply of ESs.Soil retention service generally exhibits a positive coupling type B,which means that the decrease in demand for ESs has had a negative response on the supply of ESs.3)Over the past 12 yr,the coordination degree of supply and demand of water supply,food supply and soil retention services decreased,and the coordination degree of carbon fixation service increased.Various types of ES had a low degree of couplin 展开更多
关键词 loess hilly region supply and demand of ecosystem services(ESs) coupling coordination degree elastic coefficient coupling relation
在线阅读 下载PDF
Photoacoustic imaging-guided chemo-photothermal combinational therapy based on emissive Pt(Ⅱ)metallacycle-loaded biomimic melanin dots 认领
19
作者 Chonglu Li Pei-Pei Jia +7 位作者 Yu-Ling Xu Feng Ding Wen-Chao Yang Yao Sun Xiao-Peng Li Guang-Qiang Yin Lin Xu Guang-Fu Yang 《中国科学:化学英文版》 SCIE EI CAS 2021年第1期134-142,共9页
Pt(Ⅱ)-based metallacycles,as an important family of supramolecular coordination complexes(SCCs),have exhibited excellent antitumor activity at the cell level.However,the biomedical applications of Pt(Ⅱ)-based metall... Pt(Ⅱ)-based metallacycles,as an important family of supramolecular coordination complexes(SCCs),have exhibited excellent antitumor activity at the cell level.However,the biomedical applications of Pt(Ⅱ)-based metallacycles for animal studies are still hindered by their poor stability,non-targeted tumour,and lack of detectable feedback for evaluating therapeutic progress.Herein,we propose a strategy that introduces melanin dots as a biomedical platform to load bright-emission Pt(Ⅱ)-based metallacycles,thereby constructing a theranostic agent that enables photoacoustic imaging(PAI)-guided chemo-photothermal combinational therapy.Melanin dots act as a protective carrier to preserve the integrity of Pt(Ⅱ)-based metallacycles before uptake by tumour tissues.Meanwhile,the PAI signal from melanin dots furnishes more comprehensive information on the tumour.Moreover,the heat generated after NIR laser irradiation can not only trigger the apoptosis of tumour cells but also promote the deeper penetration of Pt(Ⅱ)-based SCCs into tumour tissue,thus enhancing the efficiency of chemotherapy. 展开更多
关键词 METALLACYCLES supramolecular coordination complexes chemo-photothermal therapy photoacoustic imaging melanin dots
体育产业与城市化耦合协调发展的实证研究——以上海市为例 认领
20
作者 任波 黄海燕 《河北体育学院学报》 2021年第1期26-34,共9页
运用熵值法和耦合协调评价方法,对体育产业与城市化耦合协调发展进行研究。在探析体育产业与城市化耦合协调机理的基础上,构建体育产业与城市化评价指标体系,并以上海为案例进行实证分析。结果显示:①体育产业能够为城市化发展提供强劲... 运用熵值法和耦合协调评价方法,对体育产业与城市化耦合协调发展进行研究。在探析体育产业与城市化耦合协调机理的基础上,构建体育产业与城市化评价指标体系,并以上海为案例进行实证分析。结果显示:①体育产业能够为城市化发展提供强劲动力,城市化能够为体育产业发展创造良好条件;②2014—2016年上海体育产业综合发展水平低于城市化综合发展水平,2017—2018年则高于城市化综合发展水平;③2014—2016年上海体育产业与城市化耦合发展状态为体育产业滞后型耦合,2017—2018年为城市化滞后型耦合;④2014—2018年上海体育产业与城市化耦合协调程度由极度失调发展至初级协调,2014—2016年为体育产业滞后型耦合协调,2017—2018年为城市化滞后型耦合协调。针对以上问题提出相应对策,旨在提升二者耦合协调水平。 展开更多
关键词 体育产业 城市化 耦合 协调 上海
在线阅读 免费下载
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈